In sports, it`s the back up quarterback.

In theater, it`s the understudy.

When the person with the lead can`t perform someone steps in to fill therole.

The GEO Tracker four-wheel-drive utility vehicle from Chevrolet is one of those role players. When you don`t need the family sedan or van for that shortrun or light haul, Tracker gets the job done.

What you have to understand going in is that Tracker has limitations,based mostly on size.

Tracker comes in hardtop and convertible versions. We drove theconvertible with snap on/off removable plastic top and two tiny seats in back for adventurous passengers.

The strengths are cute looks, fun in the sun and wind in your facemotoring, high mileage and four-wheel-drive pulling power in the Snow Belt.

Weaknesses are rough ride, a noisy passenger compartment from the soundmagnifying plastic top and less than confidence-building handling when thewinds are blowing across the road north to south and you`re traveling east to west.

The pint-size Tracker is built on an 86.6-inch wheelbase and is 142.5inches long overall, or slightly bigger than the 79.9-inch wheelbase and 135- inch length on the Suzuki Samurai from which it sprang.

The Samurai, you may recall, got rapped over fears of potential rollover, not to mention concern over being the lilliputian of four-wheelers. To easethe fears, Suzuki built a larger model called Sidekick and supplies Chevrolet with the Tracker version. But obviously not all fears over the Samurai havebeen eased, considering a 53 percent decline in 1989 model year sales.

Though Tracker has more stability than a Samurai, you sit close to thoseaxles, so accept the fact this is a big step down in smoothness from a ChevyBlazer S-10.

We drove it on the interstate when the winds were gusting. It seemed that for every mile we logged in a straight line, we must have run up a quarter of a mile swaying sideways.

The wind also played havoc with normal conversation. When the wind ishowling, two things are advised with the plastic top, turn the radio up anotch to drown out the sound of plastic crackling and turn the heater up anotch to keep yourself from crackling.

Tracker attraction is the cuteness of being a miniaturized four wheelerfor those who can`t afford the larger S-10 Blazer or Ford Bronco II or JeepWrangler whose price stickers are in the stratosphere.

Tracker is powered by a fuel-injected, 80-horsepower, 1.6-liter, 4-cylinder engine teamed with a five-speed manual. Not a bad combo, butmileage is the primary concern not off the line power. The EPA rating is 26miles per gallon city and 28 miles per gallon highway with 5-speed manualtransmission and 24 m.p.g. city/25 m.p.g. highway with optional ($565)automatic transmission.

Standard equipment includes power brakes, 15-inch off-road tires, full-size rear-mounted spare tire, flush-mounted Halogen headlamp s, dual rear-view mirrors, tow hooks, tachometer and trip odometer.

The convertible starts at $10,725. The test vehicle added color keyedfloor mats, $28; transfer case shield, $75; spare tire cover, $33; and AM/FMstereo with cassette and digital clock, $441. With freight the sticker wasless than $12,000; add $695 if you want air conditioning.